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TJ-II:Radiation asymmetries and potential variations: Difference between revisions
TJ-II:Radiation asymmetries and potential variations (view source)
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varies according to their adiabatic response and can be written as: <math>n_{a0}=\left<n\right>\exp\left(-Z_{a}e\Phi_1/T_{a}\right)</math>, with | varies according to their adiabatic response and can be written as: <math>n_{a0}=\left<n\right>\exp\left(-Z_{a}e\Phi_1/T_{a}\right)</math>, with | ||
<math>\left<...\right></math> the flux-surface-average. In TJ-II plasmas experiments and simulations | <math>\left<...\right></math> the flux-surface-average. In TJ-II plasmas experiments and simulations | ||
<ref>M A Pedrosa ''et al.'', ''Electrostatic potential variations along flux surfaces in stellarators'' Nucl. Fusion '''55''' 052001 (2015) </ref> | <ref>M. A. Pedrosa ''et al.'', ''Electrostatic potential variations along flux surfaces in stellarators'' Nucl. Fusion '''55''' 052001 (2015) </ref> | ||
<ref> | <ref>J. M. Garcı́a-Regaña ''et al.'' ''Electrostatic potential variation on the flux surface and its impact on impurity transport'' Nuclear Fusion '''57''' 056004 (2017)</ref> | ||
have shown that <math>e\Phi_1/T_{a}</math> can take values from <math>O(0.01)</math> to <math>O(0.1)</math>. Variations are predicted to be | have shown that <math>e\Phi_1/T_{a}</math> can take values from <math>O(0.01)</math> to <math>O(0.1)</math>. Variations are predicted to be | ||
larger at the outer radii than at the inner core, and stronger in ECRH plasmas than in NBI plasmas. Under | larger at the outer radii than at the inner core, and stronger in ECRH plasmas than in NBI plasmas. Under | ||
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system <ref> M. A. Ochando ''et al.'' ''Up-down and in-out asymmetry monitoring based on broadband radiation detectors'' Fusion Sci. and Technol. '''50''' 313 (2006) </ref> after the inyection | system <ref> M. A. Ochando ''et al.'' ''Up-down and in-out asymmetry monitoring based on broadband radiation detectors'' Fusion Sci. and Technol. '''50''' 313 (2006) </ref> after the inyection | ||
of some selected impurities by gas puffing is proposed. The experiment aims at studying the relation between the radially asymmetric | of some selected impurities by gas puffing is proposed. The experiment aims at studying the relation between the radially asymmetric | ||
emissivity and the measured and predicted <math>\Phi_1</math> and compare this with the case where <math>\Phi_1</math> is neglected | emissivity and the measured and predicted <math>\Phi_1</math> and compare this with the case where <math>\Phi_1</math> is neglected | ||
<ref> J. A. Alonso ''et al.'' ''Parallel impurity dynamics in the TJ-II stellarator'' Plasma Phys. Control. Fusion. '''58'''(7) (2016). | <ref> J. A. Alonso ''et al.'' ''Parallel impurity dynamics in the TJ-II stellarator'' Plasma Phys. Control. Fusion. '''58'''(7) 074009 (2016)</ref>. | ||
The measurement and evolution of <math>\Phi_1</math> will be tracked | The measurement and evolution of <math>\Phi_1</math> will be tracked | ||
during the discharges using the duplicated Langmuir probe system plasma floating potential measurements. | during the discharges using the duplicated Langmuir probe system plasma floating potential measurements. | ||